Contents

When discussing the anatomy of the human body, it is useful to first define a standard position in which the body will be presented. This standard allows the relative position of parts of the body to be described accurately and with less confusion. Anatomists use the anatomical position. A person in the anatomical position is standing up straight, with arms at the sides and palms facing forwards with the fingers extended. The feet are facing forward, as are the head and eyes (see the figure to the right).

Three planes through the body are used to describe the position and orientation of parts of the body. These are:

Median or Sagittal plane - This plane runs through the body from the head (cephalic end) to the feet (plantar end). A cut on the sagittal plane of humans creates a right and left bilaterally symmetrical half. Any plane parallel to this through the body is known as a para-sagittal plane.

Coronal plane/lateral/frontal - This plane runs through the body, also from the head to the feet, and divides the body into front and rear halves.

Transverse plane - This is any plane that runs left to right through the body and divides it into upper and lower sections.

Oblique plane - Any plane through the body that is not parallel to one of the former three.

All acts of movement are considered to be a mixture or a single contribution of the following movement terms:

Flexion - where there is a reduction in the angle between bones or parts of the body. This term applies only to movement along the sagittal or median plane. An example of arms flexing is lifting a dinner plate. When applied to the trunk of the body, this term means bowing forwards.

Extension - is the opposite of flexion, and there is an increase in the angle. This term applies only to movement along the sagittal or median plane. With the trunk of the body, this movement is bowing backwards.

Adduction - where there is a reduction in the angle between bones or parts of the body. This only applies to movement along the coronal plane.

Abduction - the exact opposite, with an increase in the angle. Also only applies to movement along the coronal plane.An example of this is where extending arms outwards as if to fly.

Rotation - is rotation of an entire limb laterally (away from the body) or medially (towards the midline of the body).

Pronation - this is the rotation of the hand so that the palm faces posteriorly. This is not medial rotation as this must be performed when the arm is half flexed. Prone means the hand is facing posteriorly.

Supination - the rotation of the hand so that the palm faces anteriorly. The hand is supine (facing anteriorly) in the anatomical position.

Protrusion - is the anterior movement of an object. This term is often applied to the jaw.

Retrusion - the opposite of protrusion.

Elevation - superior movement. This term is often applied to the shoulders (eg shrugging shoulders is elevation)

Depression - inferior movement, opposite of elevation.

Circumduction - is a special case of movement involving adduction, flexion, extension and abduction. The resulting movement creates a circular path of movement. Circumduction can be done in the hip, shoulder, thumb and fingers.

There are several cases where the meaning of the anatomical planes and terms are slightly different. Hence new definitions for movement applies. This is apparent in the foot, the tongue, the hand, the penis, the eyes, and the brain.

In the anatomical position, the penis is considered to be erect and pointing upwards, i.e. the dorsal side of the penis is what one would normally call its top side (meaning the side that would touch the belly).

The tongue has a dorsal side which is facing upwards (the side that tastes).